And although in the short term, ketogenic diets seem safe for healthy people, we also lack long-term data on the diet, so it’s hard to confirm long-term safety with certainty. Complications seen with kids maintaining a ketogenic diet for epilepsy, for example, included kidney stones, constipation, gastrointestinal issues, pancreatitis, and vitamin D and calcium deficiencies.

The most science-backed performance-boosting supplements, such as creatine monohydrate, beta-alanine, and caffeine, are all A-OK on the ketogenic diet. So, if you take a pre-workout, you should be able to continue without issue. I would also recommend gulping down some bouillon before your session to ensure your sodium and magnesium levels are on point.


If you're a protein-lover, you may think this diet is for you considering all the other foods that are eliminated. But the diet requires that protein make up 20 to 25 percent of total calories—so eating too many eggs or chicken breasts can make you top this protein amount pretty easily. (Related: 8 Common Keto Diet Mistakes You Could Be Getting Wrong)

"The keto diet is primarily used to help reduce the frequency of epileptic seizures in children. While it also has been tried for weight loss, only short-term results have been studied, and the results have been mixed. We don't know if it works in the long term, nor whether it's safe," warns registered dietitian Kathy McManus, director of the Department of Nutrition at Harvard-affiliated Brigham and Women's Hospital.
The good news is that snacks are totally allowed (and I're not just talking about carrot sticks.) There are plenty of packaged options out there designed for keto fans. FATBAR is one of them. These snack bars have 200 calories, 16 grams of fat, and four grams of net carbs. They're also plant-based and are made with almond or cashew butter, cocoa butter, coconut, pea protein, sunflower seeds, and chia seeds.
There are three instances where there’s research to back up a ketogenic diet, including to help control type 2 diabetes, as part of epilepsy treatment, or for weight loss, says Mattinson. “In terms of diabetes, there is some promising research showing that the ketogenic diet may improve glycemic control. It may cause a reduction in A1C — a key test for diabetes that measures a person’s average blood sugar control over two to three months — something that may help you reduce medication use,” she says.
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